I am a post-doc in the USA and was a teaching assistant in the same university. During my TA appointment, I attended a one-week course outside the city. Prior to leaving, I got permission from the head TA, e-mailed the course instructors, and got one of my colleagues to cover my class and office hours.
One day before my return, I got an email from the instructors asking why I was absent from the classes. I apologized and explained everything, but they were furious. A week later, I got an email that I was terminated. No reason was given, and I got no reply to my e-mails. I even called HR and got nowhere, but was told that I would be financially compensated.
I feel that this was unfair, particularly since another TA had done exactly the same thing and nothing happened to her. I do not think they should get away with this. My research PI wants to get involved since he thinks I was not treated fairly. What should I do next?
UPDATE: I took permission from the head of TA.. instructors told us in the orientation that she is the one in charge. I had one of my colleague who did the same and was not fired! I got one of my fellow TAs to cover my discussion section in exchange to cover her grading which I did! They treated me unfairly as I told them even to take the salary from me for that week. When I mentioned that another colleague did the same and I feel I am biased against, they did not reply. I asked her and she also took the permission from the head of TAs. I do not want money from them but this might show up on my record in the future and I never had any red flags in my resume and I feel I am discriminated against!